Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2018TAHOE LT, 4WD, GASREPAIR AND DIAGNOSISBODY & FRAMEWINDOWSFIXED AND MOVEABLE WINDOW SYSTEMDIAGNOSTIC INFORMATION AND PROCEDURESDTC B0283: REAR DEFROST CIRCUITCIRCUIT/SYSTEM TESTING
2018 Chevrolet Tahoe LT, 4WD, Gas
Circuit/System Testing
2018 Chevrolet Tahoe LT, 4WD, GasSECTION Circuit/System Testing
- Ignition OFF, disconnect the KR5 Rear Defogger Relay
- Disconnect the KR4B Outside Rear View Mirror Heater Relay.
- Connect a test lamp between the control circuit terminal 65 and the ground circuit terminal 60 at the KR5 Rear Defogger Relay, Engine Running.
- Verify the test lamp turns ON and OFF commanding the Rear Defogger Command ON and OFF with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, remove the test lamp, disconnect the harness connector at the K33 HVAC Control Module.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.
- If the test lamp is always ON
- Ignition OFF, remove the test lamp, disconnect the harness connector at the K33 HVAC Control Module, Engine Running.
- Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module.
- Go to next step: If the test lamp turns ON and OFF
- Test or replace the KR5 Rear Defogger Relay or the KR4B Outside Rear View Mirror Heater Relay.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.